Questions tagged [sorting]

This challenge is intended to be solved by sorting, ordering, or otherwise organizing some set of data.

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105
votes
17answers
5k views

Xorting an array

Conceptually, this challenge is really simple. You're given a list of non-negative integers ai. If possible, find a non-negative integer ...
100
votes
20answers
8k views

Sort a list and write some English!

Your boss managed to read the secret hidden message. He didn't end up firing you, though, he just made you a secretary and forbade you from writing code. But you're a programmer. You need to write ...
92
votes
41answers
26k views

Implement the Thanos sorting algorithm

The sorting algorithm goes like this: While the list is not sorted, snap half of all items (remove them from the list). Continue until the list is sorted or only one item remains (which is sorted by ...
85
votes
28answers
4k views

Vertically collapse text

Say I have text like this (each word on one line, with no spaces) Programming Puzzles & Code Golf That makes no sense! It totally defies the laws of physics. ...
71
votes
23answers
11k views

Contest: fastest way to sort a big array of Gaussian-distributed data

Following the interest in this question, I thought it would be interesting to make answers a bit more objective and quantitative by proposing a contest. The idea is simple: I have generated a binary ...
61
votes
59answers
8k views

Lossy Sorting (Implement Dropsort)

Dropsort, designed by David Morgan-Mar, is an example of a linear-time "sorting algorithm" that produces a list that is, in fact, sorted, but contains only some of the original elements. Any element ...
60
votes
18answers
4k views

There are two new sheriffs in town – Identifying DJMcMego pairs!

We have some new sheriffs moderators in town, Mego and DJMcMayhem. We need a challenge to properly honour them for their new positions, so there we go. Here's something that has caught my attention ...
44
votes
25answers
3k views

Sever-sort an array

Challenge Given a non-empty array of integers, e.g.: [5, 2, 7, 6, 4, 1, 3] First sever it into arrays where no item is larger than the previous (i.e. non-...
44
votes
16answers
4k views

Implement the “Lazy Sort”

I'm supposed to sort a list of numbers, but I'm super lazy. It's really hard to figure how to swap all the numbers around until all of them are in increasing order, so I came up with my own algorithm ...
41
votes
25answers
5k views

DropSort it like it's hot

As described in this question: Dropsort, designed by David Morgan-Mar, is an example of a linear-time "sorting algorithm" that produces a list that is, in fact, sorted, but contains only some of ...
40
votes
59answers
8k views

List of possible birth years of living humans

The Challenge Output a list of years that starts with the current year and ends 120 years ago. The birth year of every living human would be included in this list. Details The list should be in ...
38
votes
32answers
4k views

Output numbers up to 2^n-1, “sorted”

Take a positive integer n as input, and output (some of the) decimal numbers that can be created using n bits, ordered in the following way: First list all the numbers that can be created with only ...
38
votes
37answers
4k views

The Rien Number

The Champernowne constant is a number that is constructed by concatenating the first n numbers, with n tending to infinity. It ...
36
votes
9answers
5k views

Eating Candy in the Correct Order

When it comes to eating candy, I hold myself to higher standards than the typical layperson. There is a delicate balance between "mixing it up" and "saving the best for last." In this challenge, you ...
35
votes
69answers
15k views

Sort numbers by binary 1's count

Goal Write a function or program sort an array of integers in descending order by the number of 1's present in their binary representation. No secondary sort condition is necessary. Example sorted ...
35
votes
9answers
2k views

Indentation-based Sort

Given an ordered list of same-case letter strings (a-z XOR A-Z) where each string is preceded by 0 or more space ( ) characters, output the same list but with the strings sorted at each level of ...
33
votes
22answers
3k views

Sort the climbing grades

My first code golf post, apologies for any mistakes... Context In rock climbing (bouldering specifically), the V/Vermin (USA) climbing grades start at 'VB' (the easiest grade), and then go 'V0', 'V0+...
33
votes
9answers
4k views

A “Sorting” algorithm

There is a "sorting algorithm" sometimes called Stalin sort in which in order to sort a list you simply remove elements from the list until it is sorted in increasing order. For example the list <...
32
votes
16answers
3k views

This is the sort of challenge that bytes

I need to stop thinking of punny names Your task is to create as many snippets (programs that have input and output built-in), functions or full programs as possible that sorts whatever your language'...
32
votes
2answers
6k views

Implement QuickSort in BrainF*** [closed]

As discussed in the Lounge room on Stack Overflow: if you can't implement the Quicksort algorithm given en.wikipedia.org/wiki/Quicksort in any language you have minimal knowledge of, you might want ...
32
votes
6answers
1k views

Sort the Textbooks

Sort the Textbooks School is starting soon (if it hasn't already) and so it's time to get our textbooks in order. You need to sort your books in alphabetical order but that takes too long so you ...
31
votes
8answers
3k views

Sort these James Bond ratings

Introduction My grandpa is a fan of James Bond, but he is always unsure on how to rank his favourite actors. As such, he is always making lists, which is a lot of work. He asked me to produce a ...
30
votes
29answers
2k views

Interleave strings

Inspiration.* I cannot believe we have not had this challenge before: Task Given one or more printable ASCII strings, interleave them by taking one character from each string, cyclically until out ...
30
votes
17answers
2k views

Show the Top Five Comment Scores on a SE Post

A Stack Exchange script determines which five comments on questions or answers are initially seen on the main page of sites through the number of upvotes on them; the five comments with the highest ...
30
votes
17answers
3k views

A quine of sorts

Given a string x, output the characters in x sorted according to the order of appearance in your source code. Examples ...
30
votes
8answers
2k views

Visualize Merge Sort

Merge sort is a sorting algorithm which works by splitting a given list in half, recursively sorting both smaller lists, and merging them back together to one sorted list. The base case of the ...
29
votes
26answers
4k views

Arrow those variables!

Challenge Robin likes having his variables declaration in the shape of an arrow. Here's how he does it: Input any number of strings Order them by ascending length Output them ordered by the middle ...
29
votes
25answers
3k views

Sort a string, sort of

If you sort a string you'll typically get something like: ':Iaaceeefggghiiiiklllllmnnooooprrssstttttuuyyyy Yes, that was the first sentence sorted. As ...
29
votes
40answers
2k views

Implement Bogosort

Is solving Sudoku too hard? Even the brute force version? Here's a coding exercise that's a little easier. I hope. :-P Write the shortest function to implement bogosort. In specific, your function ...
29
votes
21answers
1k views

Swap indices and values

The task Write a program or function whose input is a list/array X of integers, and whose output is a list of sets of integers Y, such that for each element e in each set Y[i], X[e] = i, and such ...
29
votes
8answers
2k views

Perform gravity sort

Challenge Given a list of integers, show how gravity sort would be done. Gravity Sort In gravity sort, imagine the numbers as rows of asterisks. Then, everything falls, and the new rows will be ...
29
votes
8answers
2k views

Tell me how to flop

As computer scientists, you're probably all familiar with the basic list operations of pop and push. These are simple operations that modify a list of elements. However, have you ever heard of the ...
28
votes
12answers
4k views

Flipping pancakes

In pancake sorting the only allowed operation is to reverse the elements of some prefix of the sequence. Or, think of a stack of pancakes: We insert a spatula somewhere in the stack and flip all the ...
27
votes
41answers
2k views

Enumerate each series of identical numbers in-place

Given a list of strictly positive integers, go through each distinct number and replace all occurrences of it with successive indices (zero or one based) of a new series. Examples ...
27
votes
24answers
3k views

Sort this, quick!

Well... there are 59 (now 60) questions tagged sorting, but no simple quicksorts. That must be fixed. For those unfamiliar with quicksort, here is a breakdown, courtesy of Wikipedia- Pick an ...
26
votes
36answers
4k views

Implement Lazy Drop Sort

This challenge already describes dropsort. However, I'm kinda lazy and I really only need my array to be a bit more sorted than before, it doesn't need to be sorted all the way. In Drop Sort, we drop ...
26
votes
29answers
2k views

Ordering a list

Summary Given a list of integers, return the index each integer would end up at when sorted. For example, if the list was [0,8,-1,5,8], you should return ...
26
votes
24answers
2k views

Post-determined Array Sorting

Input: An array containing three integers: 0, 1 and 2 in any order (i.e. ...
25
votes
33answers
7k views

Sort a list of numbers [closed]

About Code-Bowling: In golf, you try to get the lowest score (smallest application, most elegant, etc). In Bowling, you try to get the highest score. So if you follow, the goal of a Code-Bowling ...
25
votes
31answers
3k views

Driftsort an array

Driftsort is a simple way to "sort" an array. It works by "sliding" or "rotating" the elements over in the array until the array is sorted, or until the array fails to be sorted. Let's walk through ...
24
votes
61answers
7k views

Find the longest word in an array

Your challenge is to take an array of strings and output the longest string in the array. So for ["tiny", "small", "bigger", "biggest"] the output would be ...
24
votes
20answers
2k views

Imitate an ordering

Given two lists of numbers, a source and a pattern, reorder the source to match the relative ordering of the pattern. Any two entries of the reordered source should compare the same way as the entries ...
24
votes
18answers
5k views

PronunciationSort™

We all know of different fancy sorting algorithms, but none of these give us numbers in a way that's easy to pronounce. To remedy this, I propose using PronunciationSort™, the most natural way to sort ...
24
votes
29answers
2k views

Rearrange a number into alphabetical order

Given a non-negative integer (n), create a function that returns n in alphabetical order, according to the literal spelling of ...
23
votes
36answers
4k views

Reliably Broken Sort

Given a list of positive integers that contains at least 3 distinct entries, output a permutation of that list that isn't sorted in ascending or descending order. Examples ...
23
votes
25answers
3k views

Numbers Increase While Letters Decrease

Inspired by this Stack Overflow question: Sorting a list: numbers in ascending, letters in descending. Your task is to solve the following problem and, as this is code-golf, you should do so in as few ...
23
votes
25answers
2k views

Sort by Largest Digit(s)

Challenge: Given a list of integer, sort descending by their single largest digit(s). The order for numbers with the same largest digit are then sorted by second largest digit, etc. We ignore ...
23
votes
26answers
2k views

Find The Rank Of A Word

Definition The rank of a word is defined as the position of the word when all the possible permutations (or arrangements) of its letters are arranged alphabetically, like in a dictionary, no matter ...
23
votes
9answers
2k views

Sort a nested list

You must write a program or function that sorts a nested list. Here are the rules for sorting a nested list: Let's take this list as an example: ...
23
votes
11answers
1k views

Fairly rank values

Task Given an input list of integers x1…xn, compute a list of ranks r1…rn (a permutation of {1…n}) so that xr1 ≤ xr2 ≤ … ≤ xrn. Then, for each xi, replace its rank by ...